1. Field of the Invention
This invention pertains to a two-dimensional colorimeter to measure the chromaticity of various samples at multiple points.
2. Description of the Prior Art
Color is considered increasingly important in various industrial areas. In the areas of painting, printing, textile, ceramics, agriculture, forestry and fishery, as well as in many other areas, chromaticity data such as spectral reflectance and calculated chromaticity of various samples are used in production lines and elsewhere.
Generally, spectrophotometers and photoelectric colorimeters are used for the measurement of chromaticity in the areas described above. In the case of a spectrophotometer, chromaticity is measured by separating the light from the sample into primary wavelength elements using a diffraction grading or spectral filter and detecting the intensity of each primary wavelength element. As a result, a spectrophotometer is capable of accurately measuring absolute chromaticity. However, the construction necessary for performing spectral separation is complex, which makes the equipment large in size as well as expensive.
On the other hand, a photoelectric colorimeter has optical filters approximating the tristimulus values, and measures the chromaticity by detecting the intensity of the light passing through these optical filters. Consequently, a photoelectric colorimeter can be an inexpensive instrument with a simple construction. However, because the method of measurement is simpler than that of a spectrophotometer, accurate measurement cannot be obtained with this type of colorimeter.
In order to measure the color irregularity, etc. of a sample, it is necessary to employ a two-dimensional colorimeter which can measure chromaticity at multiple points on the sample surface. If a spectrophotometer is used for the purpose of the two-dimensional colorimeter to obtain two-dimensional chromaticity data, while accurate measurement can be obtained, the equipment becomes complex and large. On the other hand, if a photoelectric colorimeter is used to obtain two-dimensional chromaticity data, while the equipment can be made small and relatively simple to construct, accurate measurement cannot be obtained. This is a problem not only when measuring the chromaticity of an object but also when measuring the chromaticity of a light source.
The present invention was made in view of the above problems. It is an object of the present invention to provide a two-dimensional colorimeter of simple construction which is capable of accurately measuring chromaticity at multiple points on a sample surface.